An oxygen scavenger utilizing the oxidation reaction of an iron powder has already been widely utilized in order to maintain the quality and freshness of an article, such as food, by being hermetically sealed and housed in a gas barrier container together with the article, such as food, to remove oxygen in the container. This type of oxygen scavenger utilizes the reaction of an iron powder and oxygen in the coexistence of moisture, and, for example, one obtained by adding a metal halide to an iron powder in order to provide moisture absorption properties and promote the oxidation reaction is commercially available. However, a problem of an oxygen scavenger having such a constitution is that rusty water is produced (rusting) at high humidity and contaminates an article.
In order to solve this problem, an oxygen scavenger which is an oxygen scavenger composition containing an iron powder and a metal halide, in which an iron powder and a powder of electrolyte-containing calcium silicate, in which calcium silicate and calcium chloride are mixed, are mixed, and an oxygen scavenger in which a large amount of activated carbon is further blended into the above oxygen scavenger are proposed (see Patent Document 1).
On the other hand, a problem of an oxygen scavenger containing an iron powder as the base compound (substance to be oxidized) is that metal incorporation inspection cannot be conducted because the oxygen scavenger is responded by a metal detector. In order to avoid this, as an oxygen scavenger containing an inorganic compound as the base compound, for example, an oxygen scavenger composed of a first component composed of at least one of a thiosulfate and a polyhydric alcohol, a second component composed of an alkaline compound, a third component composed of at least one of aluminum, tin, and zinc, and a fourth component composed of at least one of water, water of crystallization, and water vapor is proposed (see Patent Document 2).